The Milky Way has a disc shape. At the same time, it is formed by a cloud of stars that are located outside this disk. Astronomers have been convinced for many years that this cloud, or stellar halo of the Milky Way, is more or less spherical in shape. According to a new scientific study, published on newspaper The astronomical journalbut the shape of the hall of our Galaxy is different.
Jiwon Han of the American research center Harvard-Smithsonian Center for Astrophysics and his colleagues processed the results of modern observations of stars in our Galaxy and concluded that the galaxy’s stellar halo is actually shaped like a rugby ball or perhaps an airship. Furthermore, it is inclined with respect to the plane of the galactic disk.
The important shape of the room of the stars
A seemingly simple discovery will have far-reaching consequences. The shape of the stellar hall is closely related to a number of other phenomena, including the history of the Milky Way and, more generally, the evolution of galaxies. It also has a close link to dark matter, which according to current theories should surround the Milky Way and other galaxies.
The stellar halo of our Galaxy (photo: Harvard & Smithsonian, Melissa Weiss, CC BY 4.0)
„The shape of the star room is actually a crucial parameter that my colleagues and I have measured with unprecedented precision,“ Han explains. „The fact that it is shaped like an angled rugby ball rather than a sphere is reflected in a number of other things.“
Han’s coach and colleague Charlie Conroy furthermore supplies: „For many years everyone believed that the stellar halo was spherical and more or less isotropic, that is, the same in all directions. We now know that we can throw away the images of the Milky Way surrounded by a spherical halo that textbooks are full of.“
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The quest on the star room is very complicated. It is much thinner than the galactic disk and its stars merge with those of the disk. The researchers used two main sources of data: from observations by the European Space Observatory Gaia and from the terrestrial relief of the sky H3 (Hectochelle in the Halo at High Resolution), which took place at the MMT Observatory, located on Mount Hopkins in Arizona.
